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Students are expected to:
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| Equipment: Given by the activity 5.
Resources: http://www.makingcosmetics.com/articles/02-making-emulsions-for-cosmetics.pdf |
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The amounts suggested in recipes are often quite large. Since all the groups (optimal group size would be 4-5) need to be able to use the materials available, it should be noted that the amount of the product that is to be made should not exceed 50ml (50g). The amounts of the ingredients should be proportionally reduced if needed. Students attention should be brought to the safety issues: Using a water bath for melting waxes and fats may be related to the risk of getting burned by hot water or oil. Students will be able to mix emulsion cream together within one lesson if all necessary ingredients and tools are provided beforehand and students have a clear understanding of what should be done. Water-soluble substances should first be mixed with an aqueous phase; oil-soluble substances with an oil phase. Both of these mixtures should be heated simultaneously to 75-80°C while stirring constantly. To heat the fat basis of the cream, the dish containing it should be placed in a water bath (a larger tin bowl half filled with water, into which a smaller tin bowl can be fitted). When both cream bases reach the required temperature, remove the container with the water basis from the heating plate, the bowl with the fat basis along with the water (in the bath) should be kept warm (in the case of an electrical stove, keep it at the lowest temperature level). Next pour the fat basis into the water basis in a thin stream, at the same time stirring the mix constantly. For mixing purposes a mixer or a whisk is ideal. The mixer should be working at a medium speed. Keep on stirring and place the cream mixture back into the water bath, to avoid its rapid cooling. Continue stirring for the next 5 minutes. The mixture should be evenly creamy. Next remove the cream basis from the water bath and cool it down to 40°C while stirring at the same time. The mixer should now be working at the lowest possible speed. The less the cream comes into contact with air, the better the end result. The thickness of the cream depends on the length and intensity with which the mixture was stirred. If necessary, remove the thicker mass of the cream from the walls of the dish. At 40ºC preservatives, E-vitamins, moisturisers, etc. can be added one by one without stopping the stirring. If the additives are of different thickness, start with the thickest one |
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